This invention relates to a method for the parallel development and screening of novel materials with coated layers having useful properties that need to be identified very rapidly. It further relates to apparatus for practising the method.
When coated materials have to be produced, it is often necessary to apply various layers on top of each other. Most of the time it is desired that the ingredients of the layers do not intermix during coating. Coated materials that can be prepared in this way include inter alia ink jet receptive media, electrophotographic receptive media, photographic films, conductive films, food products such as biscuits and chocolates, multi-layer automotive coatings, paper products, such as packaging materials and paper towels, conductive films, X-ray screens, diagnostic materials such as diagnostic strips, etc.
New products, in the areas described above, need to be brought to the marketplace rapidly in a world of increasing competition and ever shortening lifecycles. Enormous pressure remains on RandD in order to test out different material combinations in a period of time that is as short as possible. Traditional methods of experimenting often lead to materials with useful properties that come to the market too late. In traditional chemical industries this dilemma has been tackled by the introduction of new approaches that can accelerate e.g. the discovery process of new drugs compared with traditional ways of experimenting. The approach of combinatorial chemistry and high-throughput screening methods is extremely powerful for investigating problems in a multi-dimensional space for materials whose properties can rely upon a very large number of parameters.
In the chemical field this combinatorial process involves the design and synthesis of high-density discovery libraries aimed at exploring large numbers of structurally or compositionally diverse compounds thought to have a significant chance of ruling the characteristics of the end product, but for which the conventional number of experiments to set up to screen all these components for useful properties is too large to be conducted. By combinatorially varying ingredients, process and reaction conditions, the total number of experiments one can screen rises exponentially, which drastically increases the chances of identifying a new material with interesting new and desired properties.
In recent years combinatorial chemistry methodologies have been increasingly applied to the field of materials science, including homogeneous and heterogeneous catalysis, phosphors for luminescent materials, etc . . . An excellent review has been presented by Jandeleit et al., Angew. Chem. Int. Ed., 1999, 38, 2494-2532. Many references to material design by combinatorial techniques can be found in this review. Combinatorial search for advanced luminescence materials has also been described in Biotech. and Bioeng. (Combinatorial Chemistry), vol. 61, no. 4, pp. 193-201. Combinatorial techniques for developing new materials have also been extensively used in the patent literature: e.g. U.S. Pat. No. 5,985,356, U.S. Pat. No. 6,004,617, U.S. Pat. No. 6,030,917, U.S. Pat. No. 6,043,363, U.S. Pat. No. 6,045,671 and U.S. Pat. No. 6,034,775.
In all of these prior art descriptions of combinatorial experimental material designs, different reaction components are applied to certain regions of a substrate using sol-gel chemistry or vapour deposition coating techniques, followed by thermal treatment procedures, e.g. annealing, to produce the final product, thereby losing the coated layer structure. See, e.g., U.S. Pat. No. 5,985,356, U.S. Pat. No. 6,004,617, U.S. Pat. No. 6,030,917 and U.S. Pat. No. 6,034,775 and references cited therein for such examples.
For many applications, as described above, more than 1 coating layer, is required, one located above the other, without mixing the ingredients in adjacent coating layers and maintaining its layered structure, e.g., photographic film in which multiple layers are present, such as silver negative films comprising typically at least 7 layers that may not be intermixed. The optimisation for these kind of materials is a very laborious and time consuming task in which many different coatings have to be applied and analysed. Once finished, said materials can be screened using high throughput procedures for useful properties including, e.g., electrical, optical, physicochemical, thermal, magnetic, mechanical, chemical, morphological, physical properties etc . . .
A method for speeding up the development of multi-layered coatings by incorporating the basic ideas of combinatorial chemistry would be very welcome.
It is an object of the invention to provide a method for speeding up the development of coated materials by applying an array of various coatings on predefined regions of a single substrate.
It is a further object of the invention to provide a method for speeding up the development of multi-layered materials wherein several variants of multi-layered materials can be prepared and screened for useful properties in parallel by applying an array of various multi-layer materials on predefined regions of a single substrate.
It is a further object of the present invention to combine a method for preparing an array of various coated materials on predefined regions of a single substrate with a method for rapid parallel screening for useful properties including, e.g., electrical, optical, physicochemical, thermal, magnetic, mechanical, chemical, morphological, physical properties, etc . . . Further objects and advantages of the invention will become clear from the detailed description herein after.
The objects of the invention are realised by a method for developing layered materials, comprising the steps of :
applying, on a first region, RM, of a substrate, a first layered material, MRM, and on a second region, RN, of said substrate a second layered material, MRN, said material, MRM, being different from said material, MRN, and
screening said materials, MRM and MRN, for a useful property, wherein said layers are applied by coating from a coating solution.